GB2328660A

GB2328660A - Articulated vehicle track link and connector

Info

Publication number: GB2328660A
Application number: GB9818785A
Authority: GB
Inventors: Paul Martin Hagger
Original assignee: William Cook Cast Products Ltd
Current assignee: William Cook Cast Products Ltd
Priority date: 1997-08-29
Filing date: 1998-08-28
Publication date: 1999-03-03
Anticipated expiration: 2018-08-28
Also published as: AU8990398A; ZA987776B; WO1999011506A1; GB2328660B; GB9718287D0; GB9818785D0

Abstract

An articulated vehicle track unit comprises two links 1, two pins 3 each passing through one of the links and an end connector for connecting the pins of adjacent links. The end connector comprises a stepped diameter retaining bolt 6 and a clamping member 5 with two recesses 7 each for receiving the end of a pin and two aligned holes 8, 9 through which the bolt can pass between the recesses. Each pin has a land 4 in its side and when the bolt is screwed into hole 8 the periphery of the bolt sits in the lands and resists removal of the clamping member from the pins. The end connector is retained by both the bolt engaging the notches and by a clamping action due to tightening the bolt. The bolt may have a taper to encourage a tight fit.

Description

Articulated Vehicle Track Link Unit and End Connector The invention relates to the connection of track links of tracked vehicles and in particular to a track link unit comprising a track link and an end connector for connecting the track pin of one track link to a track pin of an adjacent link, and to such a connector.

Conventional cast steel track links typically comprise a link plate divided into two sections separated by a spine.

Each side of the track link plate is bored through to allow the passage of elongate track pins. End connectors are clamped onto the pins such that they lie flush with the end of the pins. When a link is to be attached to an adjacent link to form an articulated track, the end connectors clamp onto an adjacent pin of an adjacent link plate.

The end connector typically consists of a metal body formed so as to provide a pair of apertures each of which is shaped to correspond with the end of the connecting pins of respective track link plates. Typically, the connecting pins have a flattened land at each end and each of the apertures in the end connector has a corresponding flattened portion. This prevents rotation of the pin in the end connector. A bolt passes through a bore in one side of the end connector and engages the other side of the connector, such as by means of a nut threadedly mounted on the end of the bolt, without contacting the pins. Tightening the nut tightens the connector so that one side of the connector is drawn towards the other thus clamping the pins in the apertures.

Problems have arisen in that despite the provision of a land on the pin and the corresponding flattened portion on the end connector, the end connectors can work loose under the load of the articulated track during use.

US 4,910,990 discloses a method of making end connectors for track link pins and describes one such connector having a connector body with through bores to accommodate the track pins. A bolt passes through the connector body perpendicular to and between the track pins and is retained in the connector body by means of a separate nut threadedly engaged with an end of the bolt and acting on an outer surface of the connector. The bolt includes a central wedge shaped portion the external surface of which contacts the external surface of the track pins.

An important consideration in the design of tracks and track components is the arduous conditions under which the tracks must operate. For example, in the case of military tanks, the vehicle and their track must operate effective in conditions ranging from sub-zero Arctic temperatures to extremely hot desert temperatures and in mud, snow, rain, water and in darkness. Furthermore, it is important to be able to replace and repair components speedily and correctly under field conditions. It is apparent that in battlefield conditions where an operative may have to repair a vehicle whilst under fire, possibly in sub-zero temperatures and with gloved hands, the number of small parts which are difficult to handle and which can easily become lost in, for example, mud must be minimised and other parts must be made as easy to handle as is reasonably possible.

Further, in providing reliable parts which are easily replaced, the ease and accuracy of production of the parts are important factors. In this respect it can be noted that tapered holes and nuts as described in US 4,910,990 are more difficult and more expensive to produce at the required close tolerance than round parallel (cylindrical) holes and bores and round parallel (cylindrical) turned components.

The present invention seeks to alleviate the above described problems of the prior art.

According to a first aspect of the present invention there is provided an articulated track link unit for a vehicle comprising: a track link including first and second track pins arranged to pass through the track link, each track pin having a concave land formed at an end region of its outer circumferential surface; and an end connector for connecting a first track pin of a first track link to a second track pin of an adjacent second track link, the end connector comprising a retaining bolt and a body part adapted to receive the retaining bolt and to receive end portions of said first and second track pins, wherein the retaining bolt includes a substantially cylindrical securing surface and the curvature of the concave lands of the track pins is substantially the same as the curvature of the cylindrical securing surface, whereby, when the track pins and the retaining bolt are received in the body part, the securing surface of the retaining bolt co-operates with the concave lands of the track pins thereby to prevent withdrawal of the track pins from the connector.

In a first preferred embodiment of this aspect of the invention, the retaining bolt comprises a central cylindrical portion forming said cylindrical securing surface disposed between an enlarged head portion and a tip portion.

Preferably, tip portion is threaded and the body part of the end connector has a bore with a corresponding internal thread for mating with the threaded tip portion of the ,bolt.

In another embodiment of this aspect of the invention, the body part of the end connector includes internal surfaces shaped substantially to conform with the respective outer circumferential surfaces of the track pins.

In an especially preferred embodiment of this aspect of the invention, the body part of the end connector is in the form of a continuous loop.

In a variation of this embodiment, said threaded bore is formed at a first side of said continuous loop and a further bore, axially aligned with said threaded bore is formed at a second side of said continuous loop.

Preferably, the diameter of the further bore is smaller than the diameter of the enlarged head portion.

It is especially preferred that as the threaded tip of the retaining bolt mates with the threaded bore, the enlarged head portion of the retaining bolt is urged against the second side of the continuous loop and the first and second sides of the continuous loop are urged towards one another. In this way, the end connector is very effectively tightened against the track pins.

Preferably, the diameter of the further bore is substantially equal to the diameter of the cylindrical securing surface.

according to a second aspect of the invention there is provided an end connector for connecting a first track pin of a first track link to a second track pin of an adjacent second track link, the end connector comprising a body part and a retaining bolt, said body part including at least one retaining bolt-receiving bore and track pin receiving orifices in which the track pins are operatively retained, which orifices have an internal surface shaped substantially to conform with the outer circumferential surface of the track pins and said retaining bolt being operatively disposed between said orifices and including a cylindrical securing surface operative to co-operate with correspondingly shaped lands of said track pins to retain the track pins in the end connector.

In a first embodiment of this aspect of the invention, the retaining bolt includes a cylindrical portion forming said cylindrical securing surface disposed between tip portion and an enlarged head portion.

Preferably, the tip portion is threaded and the body part of the end connector has a bore with a corresponding internal thread for mating with the threaded tip portion of the bolt.

In a particularly preferred embodiment of this aspect of the invention, the body part of the end connector is in the form of a continuous loop.

Preferably, in a variation of this embodiment, the threaded bore is formed at a first side of said continuous loop and a further bore, axially aligned with said threaded bore, is formed at a second side of said continuous loop.

Advantageously, the diameter of the further bore is smaller than the diameter of the enlarged head portion.

It is especially preferred that, as the threaded tip of the retaining bolt mates with the threaded bore, the enlarged head portion of the retaining bolt is urged against the second side of the continuous loop and the first and second sides of the continuous loop are urged towards one another.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made to the following drawing, in which: Figure 1 is a perspective view of one link of a track link unit in accordance with the invention. Here two end connectors including respective retaining bolts are shown.

Referring to Figure 1, a track link 1 is shown with two track link plates 2 through which two bores are provided for mounting track pins 3. Typically, the link is made from cast steel, although other suitably durable materials may be used. Beneath plates 2 rubber pads for engaging the road can be seen. Track pin 3 of the plate shown and the track pin of an adjacent link plate (not shown) are held in place within their respective bores and connected for articulation by clamping member 5 and retaining bolt 6.

Clamping member 5 comprises a continuous loop of metal with two shaped orifices or apertures 7 through which the ends of two track pins 3, from respective adjacent track link units, pass. The end connector clamping members 5 are clamped onto the pins 3 such that they generally lie flush with the ends of pins 3.

Clamping takes place as follows. A retaining bolt 6 passes through an bore 9 in one side of the end connector and engages a threaded bore 8 tapped into the other side.

Tightening the bolt 6 preferably tightens the connector so that one side of the connector is drawn towards the other thus clamping the track pins 3 in the apertures orifices. Preferably, bolt 6 passes through an enlarged hole 9 in one side of the loop so that a threaded tip portion of bolt 6A engages with an inner threaded surface of hole 8 on the opposite side of clamping member 5. Bolt 6 has an enlarged central portion 6B so that the cross section of bolt 6 is stepped. Portion 6B has a cylindrical surface and forms a cylindrical securing surface for the track pins 3. Thus, whilst the tip 6A of bolt 6 can pass into the smaller hole 8 of clamping member 5, the enlarged portion 6B is positioned between the two pins in recesses 7.

Track pins 3 have concave lands 4 which are correspondingly shaped and sized to conform with, that is, to have a close fit with the circumferential surface of portion 6B of the bolt. The lower part of bolt 6 forms an enlarged head 6C which prevents bolt 6 from passing through hole 9. On tightening bolt 6 into the threaded hole 8, clamping member 5 exerts the clamping force on track pins 3 sitting in recesses 7 as one side of the recess is drawn towards the other. The cylindrical securing surface of portion 6B of retaining bolt 6 is in contact with concave lands 4 and resists lateral removal of clamping member 5 from track pins 3.

It is important that the periphery 6B of bolt 6 is a close geometric fit with concave lands 4 so that lands 4 are securely retained on periphery 6B. Whilst a cylindrical shape for periphery 6B and a correspondingly curved concave land 4 is preferred, the outer circumferential surface of portion 6B could have a gently increasing diameter closer to head 6C so that on tightening bolt 6 in hole 8, an increasingly firm resistance fit of periphery 6B in lands 4 can be obtained.

Thus, the position of the bolt between pins of adjacent track links so that it interferes with lateral movement of each of the track pins with respect to the retaining bolt helps retain the connector on the track pins. Any movement of one pin towards the other causes the other to be more securely held by the bolt.

In Figure 1 it will be understood that an end connector and bolt can also be positioned between the two track link plates 2 so that pins 3 from one pair of track links are connected to an adjacent pair of track links by three connectors.

Whilst it is not intended that this should limit the scope of the invention, in one of the preferred embodiments, it is the combination of the clamping effect of recesses 7 as the sides of clamping member 5 are drawn together by bolt 6 and the interference of bolt 6 with both pins which increases the clamping efficacy of the end connector.

Claims

1. An articulated track link unit for a vehicle comprising: a track link including first and second track pins arranged to pass through the track link, each track pin having a concave land formed at an end region of its outer circumferential surface; and an end connector for connecting a first track pin of a first track link to a second track pin of an adjacent second track link, the end connector comprising a retaining bolt and a body part adapted to receive the retaining bolt and to receive end portions of said first and second track pins, wherein the retaining bolt includes a substantially cylindrical securing surface and the curvature of the concave lands of the track pins is substantially the same as the curvature of the cylindrical securing surface, whereby, when the track pins and the retaining bolt are received in the body part, the securing surface of the retaining bolt co-operates with the concave lands of the track pins thereby to prevent withdrawal of the track pins from the connector.

2. An articulated track link unit according to claim 1 wherein the retaining bolt comprises a central cylindrical portion forming said cylindrical securing surface disposed between an enlarged head portion and a tip portion.

3. An articulated track link unit according to claim 2 in which the tip portion is threaded and the body part of the end connector has a bore with a corresponding internal thread for mating with the threaded tip portion of the bolt.

4. An articulated track link unit according to any preceding claim in which the body part of the end connector includes internal surfaces shaped substantially to conform with the respective outer circumferential surfaces of the track pins.

5. An articulated track link unit according to any preceding claim in which the body part of the end connector is in the form of a continuous loop.

6. An articulated track link unit as claimed in claim 5 wherein said threaded bore is formed at a first side of said continuous loop and a further bore, axially aligned with said threaded bore is formed at a second side of said continuous loop.

7. An articulated track link unit as claimed in claim 6 wherein the diameter of the further bore is smaller than the diameter of the enlarged head portion.

8. An articulated track link unit according to claim 7 wherein as the threaded tip of the retaining bolt mates with the threaded bore, the enlarged head portion of the retaining bolt is urged against the second side of the continuous loop and the first and second sides of the continuous loop are urged towards one another.

9. An articulated track link unit as claimed in an of claims 6 to 8 wherein the diameter of the further bore is substantially equal to the diameter of the cylindrical securing surface.

10. An end connector for connecting a first track pin of a first track link to a second track pin of an adjacent second track link, the end connector comprising a body part and a retaining bolt, said body part including at least one retaining bolt-receiving bore and track pin receiving orifices in which the track pins are operatively retained, which orifices have an internal surface shaped substantially to conform with the outer circumferential surface of the track pins and said retaining bolt being operatively disposed between said orifices and including a cylindrical securing surface operative to co-operate with correspondingly shaped lands of said track pins to retain the track pins in the end connector.

11. An end connector according to claim 10 in which the retaining bolt has an enlarged head portion and a threaded tip portion, and the body part of the end connector has a bore with a corresponding internal thread for mating with the threaded tip portion of the bolt.

12. An end connector according to claim 11 wherein the retaining bolt includes a cylindrical portion forming said cylindrical securing surface disposed between said threaded tip and said enlarged head portion.

13. An end connector according to any of claims 10 to 13 in which the body part of the end connector is in the form of a continuous loop.

14. An end connector as claimed in claim 13 wherein said threaded bore is formed at a first side of said continuous loop and further bore, axially aligned with said threaded bore is formed at a second side of said continuous loop.

15. An end connector as claimed in claim 14 wherein the diameter of the further bore is smaller than the diameter of the enlarged head portion.

16. An end connector according to claim 15 wherein as the threaded tip of the retaining bolt mates with the threaded bore, the enlarged head portion of the retaining bolt is urged against the second side of the continuous loop and the first and second sides of the continuous loop are urged towards one another.

17. An end connector as claimed in an of claims 14 to 16 wherein the diameter of the further bore is substantially equal to the diameter of the cylindrical securing surface.

18. An articulated track link unit for a vehicle or an end connector substantially as hereinbefore described with reference to and/or as illustrated in Figure 1 of the accompanying drawings.